The present invention relates to improvements in fluidic oscillators and novel spray-forming output structures for fluidic oscillators.
In Bauer U.S. Pat. No. 4,184,636, a fluidic oscillator is disclosed which includes a chamber having a common inlet and outlet opening for which the fluid power jet is issued across the chamber. The jet impinges on a reversing wall and splits and turns so that each turned half exits through an opposite outlet port. This flow pattern contains two oppositely rotating vortices and is inherently unstable in that any small dissimilarity in the flow will abet one side while deterring the other side so that one vortex dominates the opposite or other vortex to the point where all the flow exits the one output side and the other vortex completely blocks the other output. This pattern is short lived because one vortex, being forced close to the power jet, receives fluid having higher energy than the opposite vortex. The pair of outputs was fed to an output chamber which issues a sweeping spray that was determined by the algebraic sum of two inflow components.
Stouffer U.S. Pat. No. 4,151,955 is another species of fluidic oscillator which is devoid of external feedback. In this patent, an island produces a vortex street which is shed downstream of the island or obstacle. As disclosed in this patent, various spray patterns can be generated by varying the output geometry. As disclosed in this patent, a second island may be provided in the outlet to split the output as well to control the air infiltration.